Silicones with absorption and desorption properties

Abstract

The present invention relates to novel silicone layers that exhibit excellent properties when adhered to a surface such as the skin. The silicone layer can be used, for example, as a wound contact layer for making articles such as wound dressings for promoting / supporting a wound healing process.

Description

[0001] The present invention relates to a novel silicone layer which shows excellent properties when adhered to a surface such as the skin. The silicone layer can be used, for example, as a wound contact layer for the preparation of articles such as wound dressings for promoting / supporting the wound healing process.

[0002] A wound can be considered as a separation of the contiguity of the skin tissue, where this can be combined with a loss of substances.

[0003] The healing of a wound is based on the ability of the skin to regenerate tissue such as epithelial tissue, connective tissue and supporting tissue. The regeneration of tissue is a complex occurrence of cell activities which overlap each other, where said cell activities gradually promote the healing process. A suitable wound dressing can help to provide a favorable environment for said healing process.

[0004] Such wound dressings have to be applied on a surface such as the wound or the skin around said wound. For this purpose, it is important that the wound dressing adheres well to said surface in order to prevent an undesired sliding or even removal of the wound dressing. In the field of wound dressings, it is known that polysiloxanes have several advantages such as their adhesive properties. In addition, they exhibit non-invasive properties and provide a pleasant skin feel.

[0005] Polysiloxanes (referred to herein as silicones) are also known for their hydrophobicity. However, this hydrophobicity can cause problems, for example when the patient sweats. Exudation from the wound can also cause problems. The hydrophobicity of the silicone significantly reduces the absorption rate of the accumulated exudate. In short, polysiloxanes are unable to properly absorb exudate or sweat, and the corresponding liquids remain trapped between the wound and the hydrophobic silicone. This can lead to an inhibition of wound healing or even an infection of the wound and maceration of the wound itself and the surrounding skin. In addition, due to the above-mentioned liquids, the adhesion of the wound contact layer can be negatively affected, and the wound dressing may come off, and the wound will no longer be protected.

[0006] Coloplast's patent EP 1 713 523 B1 relates to an adhesive composition which comprises a hydrophilic silicone elastomer and a hydrophobic silicone elastomer and optionally a water-absorbing material such as carboxymethylcellulose (CMC), acrylate, alginate, chitosan, polysaccharides and their derivatives or mixtures, where the ratio between the hydrophilic silicone elastomer and the hydrophobic silicone elastomer is from 95:5 to 5:95.

[0007] However, said composition seems to be improvable in terms of its structure, its absorption and desorption properties such as moisture vapor transmission rate (MVTR) and its peel properties such as the strength of the peel force.

[0008] Therefore, the object of the present invention is to overcome the above-mentioned disadvantages.

[0009] In particular, the object of the present invention is to provide a layer that can increase wearing comfort and wearing time, is sustainable and reduces waste.

[0010] Furthermore, a wound contact layer should be provided that remains in place and prevents skin maceration, even in the presence of liquids such as sweat and exudate.

[0011] Another object of the present invention is to provide a layer with breathable characteristics that allows the absorption and evaporation of exudate, and can be applied as a durable coating on substrates such as textiles or wound dressing layers, where the layer can optionally act as an adhesive.

[0012] Even further, the object is to provide a layer that accelerates the wound healing process while maintaining the positive properties of silicone. In particular, the object of the present invention is to provide a layer that can be used to absorb and desorb liquids such as exudate and sweat while maintaining the anti-trauma and adhesive properties of silicone. In other words, a wound contact layer should be provided that has an increased adsorption rate of exudate, while the strength of the peel force ensures the persistence of the position where the wound dressing has been applied.

[0013] In particular, the object is to provide a layer that can be used, for example, in wound dressings, which can ensure the strength of the peel force, the strength of the peel force ensuring the persistence at the position where the wound dressing has been applied, where the contact layer shows an increased adsorption rate from the wound and preferably transfers the adsorbed liquid to another layer of the wound dressing and / or can be prepared in a simple manner. Summary of the Invention

[0014] The present invention is suitable for solving the above-listed objects by means of a layer that contains silicone and particles of the basic salt of a specific polymer having carboxylate groups, where the silicone layer can be an adhesive layer.

[0015] Thus, the subject matter of the present invention is a layer that contains a silicone matrix with particles of the basic salt of a polymer having carboxylate groups, where the particles have an average particle size D of 1 to 40 μm 50 .

[0016] It has been unexpectedly found that a silicone layer can be provided that exhibits good absorption and desorption properties while maintaining adhesive properties such as good peel force.

[0017] Drawings

[0018] Figure 1 Shows the rheology of silicone with modified poly(meth)acrylate sodium particles at contents of 0% w / w, 20% w / w, and 30% w / w.

[0019] Figure 2Shows the water vapor transmission rate of silicone with modified poly(meth)acrylate sodium particles having different contents, wherein the modified poly(meth)acrylate sodium particles have D values of 3.73 μm and about 40 μm respectively. 50 value.

[0020] Figure 3 Shows the water vapor transmission rate of silicone at coating weights of 110 g / m² and 140 g / m² respectively and with different contents of modified poly(meth)acrylate sodium particles. 2 and 140 g / m² 2 respectively.

[0021] Figure 4 Shows the peel adhesion of silicone at a coating weight of 80 g / m² and with different contents of modified poly(meth)acrylate sodium particles. 2 respectively.

[0022] Figure 5 Shows the peel strength between a substrate (PET liner) and silicone with modified poly(meth)acrylate sodium particles having different contents, wherein the modified poly(meth)acrylate sodium particles have a D value of 3.73 μm. 50 value.

[0023] Figure 6 Shows the absorption / desorption capacity of layers with modified poly(meth)acrylate sodium particles having contents of 0% w / w and 25% w / w, wherein the modified poly(meth)acrylate sodium particles have a D value of 3.73 μm. 50 value. Detailed Description

[0024] These definitions are relevant to the embodiments of the present invention.

[0025] The meaning of the term "comprising" should be interpreted to cover all specifically mentioned features as well as optional, additional unspecified features, while the term "consisting of" includes only those specified features. Thus, "comprising" includes the meaning of "consisting of" as a limiting case.

[0026] In this application, the term "about" can be understood as ±5% of the corresponding value.

[0027] If not otherwise specified, the term "% by weight", "% w / w" should be understood to refer to the weight amount of a component relative to the total weight of the adhesive silicone layer.

[0028] The meaning of the term "alkyl" is interpreted to cover straight-chain, branched-chain, and cyclic alkyl residues. Thus, for example, "alkyl having 1 to 3 carbon atoms" covers methyl, ethyl, propyl, isopropyl, and cyclopropyl.

[0029] The term "alkylene" is construed to cover alkyl groups having at least one (unsaturated) double bond.

[0030] "Basic salt" means a salt in which the cation is a basic cation, preferably sodium or potassium, more preferably sodium.

[0031] The term "hydrophobic" may mean that the corresponding substance or compound is non-polar, insoluble in pure water and not permeated or soaked by water. The term may further mean "waterproof".

[0032] The term "hydrophilic" may mean that the corresponding substance or compound is polar and insoluble in non-polar liquids such as oil.

[0033] The term "desorption" means that a liquid that has been absorbed into a solid compound or solid object is subsequently released again. The release occurs independently and does not require further action or intervention. Absorption and release can occur on different surfaces of the object, where the release can be based on evaporation.

[0034] In accordance with the present application, silicone can be considered as a component that forms a matrix or scaffold for encapsulating particles of a basic salt of a polymer having a carboxylate group.

[0035] Generally, any silicone used in the art can be used as the silicone for forming the silicone matrix.

[0036] Silicone can be considered as a polymer containing a silicon-oxygen (...-Si-O-Si-O-Si-O-...) chain as the main chain, where two organic groups are attached to each silicon, such as (-R2Si-O-SiR2-), where the residue R is an organic group. A simple example is poly(dimethylsiloxane).

[0037] In a preferred embodiment of the present invention, the silicone chains are crosslinked, i.e., there are single bonds or linkers preferably containing no more than 15 atoms that connect the silicone chains to each other.

[0038] In a preferred embodiment of the present invention, silicone can be obtained by reacting one or more alkenyl-terminated poly(organic) siloxanes with one or more Si-H-containing poly(organic) siloxanes.

[0039] The alkenyl-terminated poly(organic) siloxane has

[0040] iA) at least one terminal silyloxy unit represented by the formula (R 1 )2(R 2 )SiO 1 / 2 wherein R 1may be the same or different and is a straight-chain or branched-chain alkyl group having 1 to 6 carbon atoms or a phenyl group optionally substituted by a straight-chain or branched-chain alkyl group having 1 to 3 carbon atoms, and R 2 is an alkenyl group having 2 to 6 carbon atoms, and

[0041] iiA) a siloxane unit represented by the formula (R 3 )2SiO 2 / 2 , wherein R 3 may be the same or different and is a straight-chain or branched-chain alkyl group having 1 to 6 carbon atoms or a phenyl group optionally substituted by a straight-chain or branched-chain alkyl group having 1 to 3 carbon atoms of an aryl unit.

[0042] In a preferred embodiment, in at least one terminal siloxane unit represented by the formula (R 1 )2(R 2 )SiO 1 / 2 , R 1 are the same and are a straight-chain or branched-chain alkyl group having 1 to 3 carbon atoms or a phenyl group, preferably a straight-chain or branched-chain alkyl group having 1 to 3 carbon atoms, more preferably methyl.

[0043] In a preferred embodiment, in at least one terminal siloxane unit represented by the formula (R 1 )2(R 2 )SiO 1 / 2 , R 1 are the same and are a straight-chain or branched-chain alkyl group having 1 to 3 carbon atoms or a phenyl group, more preferably methyl, and R 2 is vinyl.

[0044] In a preferred embodiment, the alkenyl-terminated poly(organo)siloxane contains two terminal siloxane units represented by the formula (R 1 )2(R 2 )SiO 1 / 2 , preferably two terminal siloxane units, wherein R 2 is vinyl. Such alkenyl-terminated poly(organo)siloxanes may also be referred to as vinyl-terminated poly(organo)siloxanes.

[0045] Preferably, the alkenyl-terminated poly(organo)siloxane is substantially a straight-chain polymer.

[0046] In a preferred embodiment, the alkenyl-terminated poly(organo)siloxane is a mixture of different alkenyl-terminated poly(organo)siloxanes, preferably a mixture of two to five, more preferably two different alkenyl-terminated poly(organo)siloxanes.

[0047] Preferably, the alkenyl content in the alkenyl-terminated poly(organo)siloxane, preferably the vinyl content, accounts for 0.01 to 1, preferably 0.015 to 0.8 mmol / g of the alkenyl-terminated poly(organo)siloxane.

[0048] Preferably, the alkenyl content in the alkenyl-terminated poly(organo)siloxane, preferably the vinyl content, is 0.03% to 0.35%, preferably 0.05% to 0.30%. In a preferred embodiment, there are two vinyl-terminated poly(organo)siloxanes, one having a vinyl content of 0.03% to 0.15%, preferably 0.05% to 0.12%, and the other having a vinyl content of 0.18% to 0.35%, preferably 0.22% to 0.30%.

[0049] Preferably, the viscosity of the alkenyl-terminated poly(organo)siloxane at 25 °C is 500 to 80,000 centipoise, preferably 750 to 75,000 centipoise. In a preferred embodiment, there are two vinyl-terminated poly(organo)siloxanes, preferably vinyl-terminated poly(organo)siloxanes, one having a viscosity of 500 to 2,000, preferably 750 to 1,500 centipoise, and the other having a viscosity of 40,000 to 80,000, preferably 50,000 to 75,000 centipoise.

[0050] The Si-H-containing poly(organo)siloxane has

[0051] iB) at least one terminal siloxane unit represented by the formula (H) q (R 4 ) r SiO 1 / 2 wherein R 4 may be the same or different and is a straight-chain or branched-chain alkyl having 1 to 6 carbon atoms or a phenyl optionally substituted by a straight-chain or branched-chain alkyl having 1 to 3 carbon atoms, q is selected from 1, 2 or 3 and q + r equals 3, and

[0052] iiB) a siloxane unit represented by the formula (H) s (R 5 ) t SiO 2 / 2 wherein R 5 may be the same or different and is a straight-chain or branched-chain alkyl having 1 to 6 carbon atoms or a phenyl optionally substituted by a straight-chain or branched-chain alkyl having 1 to 3 carbon atoms in the aryl unit, t is 1 or 2 and s + t equals 2.

[0053] In a preferred embodiment, in at least one terminal siloxane unit represented by the formula (H) q (R 4 ) r SiO 1 / 2 wherein R4 is the same and is a straight-chain or branched-chain alkyl group having 1 to 3 carbon atoms or a phenyl group, preferably a straight-chain or branched-chain alkyl group having 1 to 3 carbon atoms, more preferably a methyl group.

[0054] Further preferably, q is 1 or 2.

[0055] In a preferred embodiment, in the siloxy unit represented by formula (H) s (R 5 ) t SiO 2 / 2 wherein R 5 is the same and is a straight-chain or branched-chain alkyl group having 1 to 3 carbon atoms or a phenyl group, preferably a straight-chain or branched-chain alkyl group having 1 to 3 carbon atoms, more preferably a methyl group.

[0056] Preferably, t is 2.

[0057] In a preferred embodiment, the Si-H-containing poly(organo)siloxane is a mixture of different Si-H-containing poly(organo)siloxanes, preferably a mixture of two to five, more preferably two different Si-H-containing poly(organo)siloxanes.

[0058] Preferably, the Si group content in the Si-H-containing poly(organo)siloxane accounts for 0.5 to 20, more preferably 0.8 to 18, especially 1.1 to 16 mmol / g of the Si-H-containing poly(organo)siloxane.

[0059] Preferably, the Si group content in the Si-H-containing poly(organo)siloxane is 3.5% to 6.5%, preferably 4.0% to 60%.

[0060] Preferably, the viscosity of the Si-H-containing poly(organo)siloxane at 25 °C is 5 to 500 centipoises, preferably 6 to 400 centipoises. In a preferred embodiment, there are two Si-H-containing poly(organo)siloxanes, one having a viscosity of 5 to 25 centipoises and the other having a viscosity of 150 to 400 centipoises.

[0061] In a preferred embodiment of the present invention, in the reaction of the vinyl-terminated poly(organo)siloxane and the Si-H-containing poly(organo)siloxane, the molar ratio between the vinyl-terminated poly(organo)siloxane and the Si-H-containing poly(organo)siloxane can be between 1:6.5 and 1:0.2, preferably between 1:5.5 and 1:0.4, especially between 1:4.5 and 1:0.6.

[0062] In another preferred embodiment of the present invention, the reaction of the alkenyl-terminated poly(organo)siloxane and the Si-H-containing poly(organo)siloxane can be carried out in the presence of a catalyst. Generally, any catalyst suitable for carrying out the hydrosilylation reaction can be used. Preferred are platinum-based catalysts. Non-limiting examples include platinum black, chloroplatinic acid, chloroplatinic acid modified with alcohols, olefins, aldehydes, preferably platinum acetylacetonate and platinum alkanoate. Platinum can preferably be present in the corresponding catalyst in an amount between 5 and 10,000 ppm. Further, if present, the catalyst can be used in an amount between 0.001 and 0.5 by weight based on the total weight of the terminated poly(organo)siloxane and the Si-H-containing poly(organo)siloxane.

[0063] In a preferred embodiment, a poly(organo)siloxane that does not affect the reaction of the alkenyl-terminated poly(organo)siloxane and the Si-H-containing poly(organo)siloxane can be present during the reaction of the latter component. Non-limiting examples of such poly(organo)siloxanes include poly(dimethylsiloxane) and α,ω-trimethylsilyloxy-poly(dimethylsiloxane).

[0064] Further, inhibitors suitable for avoiding the start of unwanted reactions, controlling the amount of reaction and crosslinking, and / or terminating the reaction can be present. Such substances are known in the art. Non-limiting examples are tetramethylethylenetetrasiloxane, pyridine, phosphines and organophosphines, unsaturated amides, preferably alkyl maleates having 1 to 6 carbon atoms in the alkyl group, alkynols such as 1-ethynylcyclohex-1-ol, and substances generally bearing at least one alkenyl group. Based on the total weight of the alkenyl-terminated poly(organo)siloxane and the Si-H-containing poly(organo)siloxane, the substance can preferably be present in an amount between 90 and 1100 ppm.

[0065] In a preferred embodiment of the present invention, the silicone consists of a matrix of hydrophobic silicone. Hydrophobic silicone can be considered as silicone having terminal polar groups such as hydroxyl, amino and / or carboxyl groups in an amount less than 5%, preferably less than 3%, more preferably less than 1%, especially less than 0.5% based on the total number of end groups.

[0066] In addition, the hydrophobic silicone can be considered as silicone having terminal non-polar groups such as alkylene, ether and unsubstituted phenyl groups in an amount greater than 95%, preferably greater than 97%, more preferably greater than 99%, especially greater than 99.5% based on the total number of end groups. The amounts of polar and non-polar groups can be determined, for example, by integral evaluation via NMR.

[0067] The adhesive silicone layer contains particles of the basic salt of a polymer having a carboxylate group, wherein the particles have an average particle size D of 1 to 40 μm 50 . Generally, a polymer containing a carboxylate group and having an average particle size D of 1 to 40 μm can be used50 any polymer

[0068] Polymers containing carboxylate groups can be obtained, for example, by homopolymerizing monomers having carboxylate groups such as acrylic acid (H2C=CH(COOH)), methacrylic acid (H2C=CCH3(COOH)), maleic acid, itaconic acid, and vinylpropionic acid, copolymerizing two or more of the above monomers, or copolymerizing the above monomers with other monomers. Suitable other monomers are known in the art. Non-limiting examples are vinyl compounds such as N-vinylpyrrolidone; vinyl esters such as vinyl formate and vinyl acetate; vinyl ethers such as methyl vinyl ether; vinyl ketones such as methyl vinyl ketone and ethyl vinyl ketone; vinyl halide compounds such as vinyl chloride and vinyl bromide, (meth)acrylic acid alkyl esters (where the alkyl group has 1 to 6 carbon atoms) such as methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, hexyl methacrylate, optionally substituted styrene compounds such as styrene and methylstyrene, vinylidene monomers such as vinylidene chloride, acrylamide and its alkyl-substituted compounds (where the alkyl group has 1 to 6 carbon atoms), acid compounds having polymerizable double bonds, their salts and acid anhydrides such as vinylsulfonic acid, allylsulfonic acid, methallylsulfonic acid, styrenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid. Subsequently, the corresponding polymers can be converted into salts by methods known in the art.

[0069] Alternatively, polymers containing carboxylate groups can be obtained, for example, by homopolymerizing monomers having groups that can be further reacted to form carboxylate groups such as acrylonitrile, (meth)acrylic acid alkyl esters, and acrylamide and its alkyl-substituted compounds (where the alkyl group has 1 to 6 carbon atoms), acid compounds, or copolymerizing the above monomers with other monomers. Suitable other monomers are known in the art. Non-limiting examples are vinyl compounds such as N-vinylpyrrolidone; vinyl esters such as vinyl formate and vinyl acetate; vinyl ethers such as methyl vinyl ether; vinyl ketones such as methyl vinyl ketone and ethyl vinyl ketone; vinyl halide compounds such as vinyl chloride and vinyl bromide, optionally substituted styrene compounds such as styrene and methylstyrene, vinylidene monomers such as vinylidene chloride, their salts and acid anhydrides having polymerizable double bonds such as vinylsulfonic acid, allylsulfonic acid, methallylsulfonic acid, styrenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid. Subsequently, the corresponding polymers can be converted into polymers having carboxyl groups and their salts by methods known in the art.

[0070] Preferably, the polymer having a carboxylate group is a poly(meth)acrylate polymer or a poly(meth)acrylate copolymer. The polyacrylate polymer can be considered to have the formula -CH2-CH(COO θ) - repeating unit polymer, and polymethacrylate polymers can be considered to have the formula -CHCH3-CH(COO θ ) - repeating unit polymer. Preferably, the polymer having a carboxylate group is a polyacrylate or a polyacrylate copolymer, such as an acrylate / methacrylate copolymer. Alternatively preferably, the polymer having a carboxylate group is a polymethacrylate or a polymethacrylate copolymer, such as a methacrylate / acrylate copolymer. Its corresponding copolymer can further contain units from suitable monomer compounds as described above. Poly(meth)acrylate is beneficial because it does not become a gel when in contact with polar liquids and it also does not swell.

[0071] Furthermore, the polymer having a carboxylate group is preferably crosslinked. Regarding crosslinking, the same applies as described above. Preferably, crosslinking is achieved by reacting a part of the carboxyl groups or a part of the groups that can be further reacted to carboxyl groups with guanidine or its salts, optionally substituted diamines such as ethylenediamine and methylethylenediamine, or optionally substituted hydrazine or its salts.

[0072] Furthermore, it is preferred that the polymer having a carboxylate group bears basic salt carboxylate groups in an amount of 1 to 15 meq / g, preferably 2 to 12 meq / g, more preferably 3 to 10 meq / g based on the weight of the polymer having a carboxylate group.

[0073] The particles of the basic salt of the polymer having a carboxylate group have an average particle size D of 1 to 40 μm, preferably 2 to 35 μm, more preferably 3 to 30 μm 50 .

[0074] In the context of the present invention, the expression "average particle size" can be related to the D value of the average particle size. 50 In the context of the present invention, the average particle size (which is also referred to as the D value of the integral volume distribution) is defined as the particle size at which 50% by volume of the particles have a size smaller than the size corresponding to the D value. Similarly, 50% by volume of the particles have a size larger than the D value. 50 value) is defined as the particle size at which 50% by volume of the particles have a size smaller than the size corresponding to the D 50 value. Similarly, 50% by volume of the particles have a size larger than the D 50 value.

[0075] In a preferred embodiment of the present invention, the particles of the basic salt of the polymer having a carboxylate group have a particle size (D 90 ) of 3 to 100 μm, preferably 5 to 90 μm, more preferably 6 to 80 μm. In the context of the present invention, the D value of the integral volume distribution is defined as the particle size at which 90% by volume of the particles have a size smaller than the size corresponding to the D 90 value. Similarly, 10% by volume of the particles have a size larger than the D 90 value. Similarly, 10% by volume of the particles have a size larger than the D 90A size with a larger value.

[0076] Particle size D 50 and D 90 Measured according to ISO 13320:2020. Particle size D 50 and D 90 Measured by using a Mastersizer 3000 laser particle size analyzer from Malvern Instruments. It has a HydroLV liquid analysis module and an Aero S dry analysis module. Evaluated according to the Mie Theory.

[0077] In a preferred embodiment of the present invention, the particles of the basic salt of the polymer having a carboxylic ester group have a specific surface area of 0.5 to 40 m 2 / g, preferably 1 to 30 m 2 / g, more preferably 2 to 30 m 2 / g, especially 3 to 15 m 2 / g. Regarding the determination of the specific surface area, refer to European Pharmacopoeia 2.9.26 (Determination of specific surface area by gas adsorption). Measuring the specific surface area according to the BET method is carried out using grade 5.0 quality nitrogen according to ISO 9277:2010. This determination can be carried out with a Gemini VII specific surface area analyzer from Micromeritics, a Smart VacPrep degasser from Micromeritics, and a CRios-55 freeze dryer from Cyrotec.

[0078] In a preferred embodiment of the present invention, the particles of the basic salt of the polymer having a carboxylic ester group have a porosity of 10% to 75%, preferably 20% to 70%, especially 25% to 65%. The porosity is determined by mercury intrusion porosimetry according to ISO 15901-1 9277:2010. This determination can be carried out with an Autopore IV.

[0079] In a preferred embodiment of the present invention, the particles of the basic salt of the polymer having a carboxylic ester group have a total pore area of 1 to 50 m 2 / g, preferably 5 to 40 m 2 / g, especially 10 to 30 m 2 / g. The porosity is determined by mercury intrusion porosimetry according to ISO 15901-1 9277:2010. This determination can be carried out with an Autopore IV.

[0080] In a preferred embodiment of the present invention, the adhesive silicone layer may comprise one or more additional substances, such as substances having an antimicrobial effect. Such substances are known in the art. Non-limiting examples include biguanides and their derivatives, such as chlorhexidine, polyethylenebiguanide (PEB), polytetramethylenebiguanide (PTMB), or polyethylenhexamethylenebiguanide (PEHMB); polyguanides such as polyhexamethyleneguanide (PHMG), N-octyl-1-[10-(4-octylimino-pyridin-1-yl)decyl]pyridin-4-imine (octenidine), quaternary ammonium compounds such as benzalkonium chloride or cetylpyridinium chloride; triazines such as 1-(3-chloroallyl)-3,5,7-triaza-1-azoniaadamantane chloride, and tauromupirocin.

[0081] In a preferred embodiment, the adhesive silicone layer has a thickness of 20 μm to 225 μm, more preferably 30 μm to 215 μm, especially 40 μm to 200 μm and in particular 90 μm to 200 μm. Preferably, the adhesive silicone layer has a thickness of about 45 μm, about 50 μm, about 60 μm, about 70 μm, about 80 μm, about 90 μm, about 100 μm, about 110 μm, about 120 μm, about 130 μm, about 140 μm, about 150 μm, about 160 μm, about 170 μm, about 180 μm or about 190 μm.

[0082] In a preferred embodiment of the present invention, the particles of the basic salt of the polymer having a carboxylate group are present in an amount of 5% to 50% by weight, preferably 10% to 40% by weight, especially 15% to 30% by weight, 10% to 40% by weight, based on the adhesive silicone layer.

[0083] Preferably, the silicone adhesive layer has a water vapor transmission rate (WVTR) of 1000 to 25000 g / m 2 / 24 h measured upright according to DIN EN 13726. In a preferred embodiment, the silicone adhesive layer has about 2000 g / m 2 / 24 h, about 3000 g / m 2 / 24 h, about 4000 g / m 2 / 24 h, about 5000 g / m 2 / 24 h, about 6000 g / m 2 / 24 h, about 7000 g / m 2 / 24 h, about 8000 g / m 2 / 24 h, about 9000 g / m 2 / 24 h, about 10000 g / m 2 / 24 h, about 11000 g / m 2 / 24 h, about 12000 g / m 2 / 24 h, about 13000 g / m2 / 24 h, about 14000 g / m 2 / 24 h, about 15000 g / m 2 / 24 h, about 16000 g / m 2 / 24 h, about 17000 g / m 2 / 24 h, about 18000 g / m 2 / 24 h, about 19000 g / m 2 / 24 h, about 20000 g / m 2 / 24 h, about 21000 g / m 2 / 24 h, about 22000 g / m 2 / 24 h, about 23000 g / m 2 / 24 h, about 24000 g / m 2 / 24 h or about 25000 g / m 2 Water vapor transmission rate of / 24.

[0084] According to the present invention, the silicone of the matrix of the silicone layer is preferably capable of absorbing and desorbing polar liquids. In this regard, liquids such as water, sweat, blood, and wound exudate can enter the silicone layer and be temporarily retained due to the interaction with the porous particles. The stored liquid is then gradually released. The release can occur by evaporation. In addition, the release can occur along the concentration gradient. If the silicone layer is applied to the skin, the release will generally occur via the surface facing away from the skin (distal). The release (desorption) of the liquid allows the silicone matrix and the particles therein to maintain the absorption capacity. It is important to emphasize that the absorption of the silicone layer is a reversible process, and the silicone can return to its initial state by desorbing the liquid again, thus producing a very sustainable product suitable for long-term applications.

[0085] In addition, the silicone matrix of the silicone layer and the particles included therein can be free or substantially free of one or more of the following compounds: polyacrylate, resin, and fumed silica. The resin can be a silicone resin, and in particular, it can be an MQ resin, where "M" represents Me3SiO and "Q" represents SiO4. If the silicone matrix and the particles are free or substantially free of polyacrylate, another substance such as poly(methyl)acrylate can be used alternatively.

[0086] Another subject of the present invention is a method for preparing an adhesive silicone layer according to the present invention, the method comprising the following steps:

[0087] (i) Providing an alkenyl-terminated poly(organo)siloxane

[0088] (ii) A poly(organo)siloxane containing Si-H,

[0089] (iii) Adding particles of the basic salt of the polymer having a carboxylate group to the blend of the components of step (i) and the components from step (ii),

[0090] (iv) Coating the mixture from step (iii) onto a substrate,

[0091] (v) Subjecting the resulting mixture from step (iii) to a reaction.

[0092] As regards the components, the same applies substantially as described above.

[0093] Step (i) involves providing an alkenyl-terminated poly(organo)siloxane. In an alternative embodiment, only a part of the alkenyl-terminated poly(organo)siloxane is provided. Preferably, a mixture of alkenyl-terminated poly(organo)siloxanes is used. If present, the alkenyl-terminated poly(organo)siloxane may preferably contain a catalyst.

[0094] Step (ii) involves providing an Si-H-containing poly(organo)siloxane as component B. Preferably, a mixture of Si-H-containing siloxanes is used. In an alternative embodiment, if only a part of the alkenyl-terminated poly(organo)siloxane in step (i) is provided, then step (ii) may involve adding the remaining part to the Si-H-containing siloxane. Further, if present, the components of step (ii) may preferably include an inhibitor.

[0095] Step (iii) involves adding particles of the basic salt of the polymer having a carboxylate group to the blend of the components from step (i) and the components from step (ii). The basic salt of the polymer having a carboxylate group may be a salt of an alkyl (meth)acrylate or a salt of methacrylic acid.

[0096] In the context of the present invention, "blending" is to be understood as meaning the process of combining substances, the aim of which is to achieve a substantially uniform distribution of the different substances by the action of mechanical forces. Blending for the purposes of the present invention is carried out in conventional mixing devices such as tubular blenders, roll mixers, oscillating mixers, free-fall mixers, shear mixers or intensive mixers. Preferably, a tubular blender is used.

[0097] The blending time according to step (ii) can take, for example, from 0.5 minutes to 1 hour, preferably from 2 minutes to 50 minutes, especially from 5 minutes to 30 minutes.

[0098] The addition of the particles of the basic salt of the polymer having a carboxylate group can be carried out before, simultaneously with or after blending the components from step (i) and the components from step (ii). In the latter case, it is preferred to blend the whole mixture again.

[0099] Unlike the particles of the basic salts of polymers having carboxylate groups, one or more optional additional substances, such as substances having an antimicrobial effect, and optionally a polysiloxane that does not affect the reaction of the vinyl-terminated poly(organo)siloxane and the Si-H-containing poly(organo)siloxane, can be added before, simultaneously with, or after blending the components from step (i) and the components from step (ii).

[0100] Step (iv) includes coating the mixture from step (iii) onto a substrate. Preferably, the mixture from step (iii) can be coated onto the substrate using an applicator. Non-limiting examples of the material of the substrate are inert materials / polymers, such as polyethylene-based materials, polypropylene-based materials, polyester-based materials (such as materials from polyethylene terephthalate (PET)), polyamide-based materials, polyvinyl chloride-based materials, polyacrylate-based materials, polymethacrylate-based materials, polyurethane-based materials (such as materials from polyester urethane or polyether urethane), silicone-based materials, and mixtures thereof.

[0101] Furthermore, the substrate can have any form as long as the mixture from the layer of step (iii) can be coated on one side of the substrate. Preferably, the substrate is a film. The substrate can be considered as a carrier of the adhesive silicone layer and, if desired, can be removed from this carrier for application elsewhere.

[0102] The mixture from step (iii) can be coated onto the substrate in an amount of 10 to 500 g / m 2 , preferably 25 to 400 g / m2, more preferably 50 to 250 g / m 2 , especially 10 to 100 g / m 2 .

[0103] In an alternative preferred embodiment, the mixture from step (iii) can be coated onto the substrate in an amount of 0.5 to 25 g / m 2 , preferably 0.75 to 20 m 2 , especially 1 to 10 g / m 2 .

[0104] Step (v) includes subjecting the mixture obtained from step (iii) to a reaction. Through this reaction, these components are cured to form a silicone matrix containing particles of the basic salt of a polymer having a carboxylate group.

[0105] Preferably, this step is carried out under the blending conditions as described above.

[0106] Furthermore, subjecting the mixture obtained in step (iii) to the reaction is preferably carried out at an elevated temperature. As used herein, the term 'at an elevated temperature' means a temperature between 23 °C and 200 °C. 23 °C and room temperature can be used interchangeably.

[0107] Alternatively, if an inhibitor is used, the term elevated temperature as used herein means a temperature between 23 °C and 20 °C above the boiling point of the inhibitor. Thus, the inhibitor evaporates and the mixture obtained in step (iii) starts to solidify.

[0108] In a preferred embodiment of the invention, the reaction in step (v) can preferably be carried out at a temperature between 60 °C and 200 °C, preferably between 80 °C and 180 °C, particularly between 90 °C and 170 °C.

[0109] In a preferred embodiment, the reaction in step (v) can preferably be carried out at a temperature of about 60 °C, about 70 °C, about 80 °C, about 90 °C, about 100 °C, about 110 °C, about 120 °C, about 130 °C, about 140 °C, about 150 °C, about 160 °C, about 170 °C, about 180 °C, about 190 °C or about 200 °C

[0110] The time for subjecting the mixture obtained in step (iii) to the reaction preferably carried out at an elevated temperature can take, for example, from 0.5 minutes to 2 hours, preferably from 1 minute to 30 minutes, more preferably from 2 minutes to 15 minutes, particularly about 5 minutes.

[0111] Another subject of the invention is a silicone layer obtainable by the method according to the invention. The silicone layer can be an adhesive silicone layer.

[0112] According to one embodiment, the adhesive silicone layer has defined regions of different adhesive strength or peel strength. Preferably, the adhesive silicone layer has two regions of different adhesive strength or peel strength.

[0113] Another subject of the present invention is a wound dressing, which comprises an adhesive silicone layer according to the present invention and an additional layer containing an absorbent material. The absorbent material can be defined as a material capable of receiving and subsequently retaining liquids such as water or exudate. Absorbent materials are known in the art. Non-limiting examples include: compounds based on natural polymer materials such as starch, dextran, agarose, pectin, alginate, chitosan, hyaluronic acid, gellan gum, polypeptides and cellulose, where these natural polymer materials can be further processed, for example, by chemical derivatization such as forming esters and ethers or pharmaceutically acceptable salts; and compounds based on synthetic polymer materials such as polyvinyl alcohol, polyalkylene oxides, poly(meth)acrylates, poly(ethyl)acrylates, polyalkyl(meth)acrylates, polyalkyl(meth)acrylates, vinyl polymers, polycaprolactam and polycaprolactone, polyurethanes, copolymers based on polyureas and polyurethane-polyurea copolymers. In an embodiment, the absorbent material is a superabsorbent material or a foam based on a copolymer of acrylic acid and acrylamide, preferably a foam based on polyurethane, a copolymer based on polyureas and a polyurethane-polyurea copolymer. The layer containing the absorbent material also has desorption properties, i.e., the layer can desorb liquids such as water.

[0114] In a preferred embodiment of the present invention, the adhesive silicone layer is a wound contact layer. The wound contact layer can be considered as the layer in direct contact with the wound. Further preferably, the additional layer containing the absorbent material is arranged in direct contact with the adhesive silicone layer according to the present invention. Such an arrangement can, for example, have the advantage that exudate absorbed from the adhesive silicone layer on the wound side can be desorbed from the adhesive silicone layer on the opposite side of the wound and subsequently absorbed by the additional layer containing the absorbent material, while liquids such as water can be absorbed / desorbed in other ways. Further preferably, the additional layer containing the absorbent material (such as a foam) can preferably have a smaller surface area than the surface of the adhesive silicone layer of the present invention. Further preferably, the additional absorbent material layer is arranged on or adhered to the center of the adhesive silicone layer of the present invention such that the four edges of the adhesive silicone layer are not covered by the additional layer containing the absorbent material and can have substantially the same area dimensions, thereby forming a continuous edge around the center. A wound dressing having such a continuous edge is defined as an island dressing. Such an arrangement enables the adhesion of another layer (such as a backing layer) to the opposite side of the wound contact layer such that the top surface of the wound dressing is covered by the backing layer.

[0115] Exemplary part

[0116] 1. Prepare the silicone layer according to the specification

[0117] A mixture of 95 g of a vinyl-terminated poly(organo)siloxane having a vinyl content of 0.06% to 0.1% and a viscosity between 50,000 and 70,000 centipoise, 5 g of a vinyl-terminated poly(organo)siloxane having a vinyl content of 0.22% to 0.28% and a viscosity between 800 and 12,000 centipoise, and 0.005 g of a platinum catalyst (platinum acetylacetonate) is provided as Part A.

[0118] Further, a mixture of 93.3 g of a vinyl-terminated poly(organo)siloxane having a vinyl content of 0.06% to 0.1% and a viscosity between 50,000 and 70,000 centipoise, 4.9 g of a vinyl-terminated poly(organo)siloxane having a vinyl content of 0.22% to 0.28% and a viscosity between 800 and 12,000 centipoise, 1.7 g of an Si-H-containing poly(organo)siloxane having an Si-H content of 4.5% to 5.0% and a viscosity of 250 to 350 centipoise, 0.1 g of an Si-H-containing poly(organo)siloxane having an Si-H content of 5.2% to 5.8% and a viscosity of 7.0 to 20,350 centipoise, and 0.8 g of an inhibitor (1-ethynylcyclohex-1-ol) is provided as Part B.

[0119] In addition, 0 g, 10 g, 20 g, 30 g, 40 g, 50 g, 60 g, 70 g, and 80 g (corresponding to 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, and 40% by weight based on the total of Part A and Part B) of particles of the sodium salt of a modified poly(meth)acrylate (wherein the particles have an average particle size D of 1 to 40 μm) 50 are dried in an oven at 160 °C for one hour as the corresponding Part C.

[0120] Parts A, B, and C are blended to obtain mixtures M0 to M8 as shown in Table 1.

[0121] Table 1:

[0122]

[0123] Each mixture is applied in an amount of 80 g / m 2 onto a nonwoven substrate via a doctor blade of a laboratory coater. Subsequently, the silicone is cured in an oven at 140 °C for 5 minutes to obtain the silicone layer of the present invention.

[0124] 2. Properties of the silicone layer of the present invention

[0125] 2.1 Rheology of the product

[0126] The rheology was determined using a Rheometer AR 1000 with a computer equipped with software for controlling the rheometer and analyzing the results, and the procedure was as follows:

[0127] - Place the weighed silicone sample in the center of the tray of the rheometer,

[0128] - Lower the moving part and ensure that the crushed silicone covers the entire surface of the moving part,

[0129] - Remove the excess silicone if necessary,

[0130] - Start the measurement.

[0131] From Figure 1 It can be seen that the silicone layer with a high content of modified sodium acrylate particles has substantially the same rheology as the silicone without such particles. In other words, incorporating the modified sodium acrylate particles into the mixture to be cured has no negative impact on the cured product.

[0132] 2.2 Water vapor transmission rate

[0133] As described above, the water vapor transmission rate was determined vertically according to DIN EN 13726.

[0134] A) From Figure 2 It can be seen that the silicone layer of the present invention exhibits a favorably high water vapor transmission rate compared to a layer without particles of the sodium salt of modified poly(methyl)acrylate. Considering this, it is assumed that due to this property, the layer of the present invention enables the absorption of liquids such as exudate or water on one side and the desorption thereof on the other side, or vice versa.

[0135] B) Example 1 was carried out, in which the mixtures M3, M4, M5 and M6 were applied to the nonwoven substrate at amounts of 110 g / m 2 and 140 g / m 2 respectively via the doctor blade of a laboratory coater.

[0136] From Figure 3 It can be seen that even at different thicknesses (obtained by different amounts (coating weights) applied per m 2 ), the layer of the present invention also exhibits excellent high water vapor transmission rate, which is the reason for its high level of breathability.

[0137] 3. Peel adhesion

[0138] The peel adhesion was determined by the method based on FINAT n°1.

[0139] The peel adhesion of the silicone layers of the present invention with different contents of modified poly(methyl)acrylate sodium particles was measured.

[0140] From Figure 4 It can be seen that the silicone layer of the present invention has substantially the same peel adhesion as a silicone layer without poly(meth)acrylate particles. Thus, incorporation of poly(meth)acrylate particles into the silicone layer has no negative impact on peel adhesion compared to a silicone layer without the modified poly(meth)acrylate particles.

[0141] 4. Peel Strength

[0142] The peel force was determined by the following method:

[0143] - Prepare a laminated test panel consisting of two suitably prepared and bonded flexible adherends.

[0144] - Cut the bonded panel into 25 - mm test specimens by a device harmless to the bond. The unbonded ends are bent apart perpendicular to the bond line for clamping in the jaws of a tensile testing machine.

[0145] - Condition the specimens for 7 days at 23 ± 1 °C and 50% ± 2% relative humidity. Clamp the bent, unbonded ends of the test specimens in the test jaws of a tensile testing machine.

[0146] - Apply a load at a constant head speed of 254 mm (10 in.) / min.

[0147] - Automatically record the load versus the peel distance.

[0148] - Determine the peel resistance within at least 130 mm.

[0149] - Calculate the peel force.

[0150] From Figure 5 It can be seen that the silicone layer of the present invention has favorable values in terms of the peel (stripping) strength of the PET liner compared to a layer without the modified poly(meth)acrylate particles, enabling easier further processing of the layer, for example in line with the preparation of wound dressings. In other words, the reduced force required to remove the PET liner of the silicone is favorable for the processability of the material.

[0151] 5. Absorption / Desorption Capacity

[0152] The absorption and desorption capacities of the silicone layer of the present invention containing 25% by weight of modified poly(meth)acrylate particles with an average particle size D 50 with a value of 3.73 μm and a silicone layer without such particles were compared, where the absorption and desorption capacities were determined according to the following method:

[0153] - Cut circular samples of each 100 cm 2 and weigh them.

[0154] - Place the sample in water and weigh it every 5 minutes.

[0155] - After reaching the maximum absorption capacity, leave the sample outdoors and weigh it every five minutes.

[0156] - After reaching the maximum desorption, place the sample in water again and start the measurement cycle again.

[0157] From Figure 6 It can be seen that the silicone layer of the present invention can absorb and desorb moisture (water) several times, while the product without the modified poly(sodium acrylate) particles cannot absorb a large amount of moisture at all.

Claims

1. A silicone layer comprising a silicone matrix containing particles of the basic salt of a polymer having a carboxylate group, wherein the particles have an average particle size D50 of 1 to 40 μm.

2. The silicone layer according to claim 1, wherein, The silicone matrix consists of a hydrophobic silicone.

3. The silicone layer according to claim 1 or 2, wherein, The polymer having a carboxylate group is a poly(meth)acrylate polymer, preferably a polymethacrylate or a polymethacrylate copolymer.

4. The silicone layer according to any one of the preceding claims, wherein, These particles have an average diameter of 4 to 30 μm.

5. The silicone layer according to any one of the preceding claims, wherein, The particles of the basic salt of these polymers having a carboxylate group are present in an amount of 5% to 50% by weight based on the silicone layer.

6. The silicone layer according to any one of the preceding claims, wherein These particles have a porosity of 10% to 75%.

7. The silicone layer according to any one of the preceding claims, wherein, The wound contact layer has a Moisture Vapor Transmission Rate (MVTR) of 1500 to 25000 g / m 2 / 24h as measured as described in the specification.

8. The silicone layer according to any one of the preceding claims, wherein The silicone matrix is capable of absorbing and desorbing polar liquids.

9. The silicone layer according to any one of the preceding claims, wherein, The silicone matrix is substantially free of polyacrylate, MQ resin, and fumed silica.

10. A method for preparing a silicone layer according to any one of the preceding claims, the method comprising the following steps: (i) providing an alkenyl-terminated polyorganosiloxane, (ii) a Si-H-containing poly(organo)siloxane, (iii) adding the particles of the basic salt of these polymers having a carboxylate group to a blend of the component from step (i) and the component from step (ii), (iv) coating the mixture from step (iii) onto a substrate, and (v) subjecting the resulting mixture from step (iii) to.

11. The method according to claim 10, wherein, The component from step (i) further contains a catalyst, and the component from step (ii) further contains an inhibitor.

12. The method according to claim 10 or 11, wherein, Step (v) includes heating the mixture to an elevated temperature.

13. A silicone layer obtainable by the method according to any one of claims 10 to 12.

14. A wound dressing comprising a silicone layer according to any one of claims 1 to 9 and 13 and a further layer comprising an absorbent material.

15. The wound dressing according to claim 14, wherein, The silicone layer is a wound contact layer.

16. The wound dressing according to claim 14 and / or claim 15, wherein The further layer comprising an absorbent material is disposed directly on the silicone layer.

Images